"0.01" should be written as "zero point zero one." But seriously, who even writes out numbers in words these days? Just stick with the digits and save yourself the trouble of trying to remember all those pesky rules.
001 = one
Five hundred nine thousand, one.
0.000 000 001 1 x 10-9 1 nano... 0.001 micro... 0.000 001 milli...
One thousandth.
The general rule in formal writing (that which you do for school or work) is yes. All numbers that appear as two or fewer words should be written out.
001 = one
100 + 20 + 9 + 9 + 001 = 139
one-thousandth of one percent
900,001 = nine hundred thousand, one.
Steve Why has written: 'Vanuatu project performance review--VAN/96/001'
509,001 = five hundred and nine thousand and one
Five hundred nine thousand, one.
0.000 000 001 1 x 10-9 1 nano... 0.001 micro... 0.000 001 milli...
"Lab work" should be written as two words.
One millionth.
One thousandth.
The general rule in formal writing (that which you do for school or work) is yes. All numbers that appear as two or fewer words should be written out.